Fix Eclipse metadata

- Fix the issue with the Eclipse metadata that was preventing some people from importing the project.
- Add a .gitignore file for Android projects. This prevents files that shouldn't be tracked, such as binaries, from being added to the repository. It does not affect files that are already in the repository. It is possible to recursively remove them in a future commit.

https://help.github.com/articles/merging-a-pull-request